Variable condenser



De@ 9, 1941- F. J. w. scHoENaoRN VARIABLE CONDENSER Filed Oct. 25, 1939 INVENTOR. E SCHOENBORN BY #5g ATTORNLTK Patented Dec. `9, 1941 i UNITED STATT-:s PATENT OFFICEy 2.265.401 vAnIABLE coNpENsEa Ferdinand Julius W. Schoenborn, Riverhead, N. Y., asslgnor to Radio Corporation of America, a corporation of Delaware Application ctober 25, 1939, Serial No. 301,107 5 Claims. (CL 175-41.5)

This invention relates to a new and improved tial. A terminal I5 connects the xed electrode variable condenser. I to the high potential side of the radio receiver. An object is to provide an extremely accurate A split strap member I6 is arranged to surround variable condenser for use with ultra high frethe outside end of casing member 3 and supports quencies. 5 a light shield I1 which is clamped thereon by Another object is to provide a variable conmeans of a screw I8 andnut I8.` Illumination denser for use with a short wave radio receiver. on the micrometer scale is maintained by means Still another object is to provide a variable of a lamp bulb 20, the light rays of which pass condenser which will maintain extremely accuthrough a narrow slit 2I.

Although only one embodiment of this invention rate capacity calibration, regardless of temperal0 is shown, it is to be distinctly understood that ture changes.

A further object is to provide a variable conthe invention should not be limited precisely denser which eliminates noisy performance and thereto. capacity effect during operation of the unit. What is claimed is:

Afeature of this invention is the insulated var- 15 l. A variable vernier condensercomprising a iable electrode with brush contacts to ground at metallic casing member, a glass tube bearing loone point only. cated concentric within said casing, a tubular in- Another feature of this invention is the comsulator secured to one end of said casing and pact arrangement of the component parts and projecting beyond said casing end, a tubular xed the ease with which they are assembled. 0 electrode secured to the projecting portion of Still another feature is the novel scale illumisaid insulator, a movable electrode secured to nation and adjustment of the light. said casing at an end opposite said fixed elec- This invention will best be understood by refertrode, and means to vary the condenser capacity ring to the accompanying drawing, in which: by moving said movable electrode Within said Fig. 1 is a longitudinal section of the variable 'v glass tube bearingA and said xed electrode. condenser of this invention; 2. A variable Vernier condenser comprising a Fig 2 is a Cross section of Fig, 1; and metallic casing member, a Pyrexv glass tube Fig. 3 is a front elevation of Fig. l. bearing located concentric within said casing, a

Referring now in detail to the drawing, a fixed 30 tubular insulator secured to one end of said cashollow electrode I is secured by press fit into a ing and projecting beyond said `casing end, a concentric ground Isolantite insulating support tubular fixed electrode secured to said insulator. bushing 2, the latter being also fastened into a a movable electrode secured to said casing at an tubular metallic casing member 3. A ange '4 end opposite said fixed electrode, and means to being part of casing 3 supports it to a panel 5 3i, vary the condenser capacity by moving said movof a radio receiver, the forward end of casing able electrode within said Pyrex glass tube 3 is threaded to receive a. threaded end cap 6 bearing and said fixed electrode.

which clamps a bushing 1. A standard machin- 3. A variable Vernier condenser comprising a ists micrometer head 8, has its spindle 9 termimetallic casing member, a tubular insulator senating in apressed-on Isolantite bushing I0 which 4l cured to one end of said casing, a tubular xed also acts as a stop for the variable electrode. A electrode secured to said insulator and concensilver shaft II forms the other or lvariable electric with said casing, a support barrel for said trod'e secured by press fit to bushing I0. A varimovable electrode secured to said casing at an able electrode support barrel I2 is threaded to end opposite' said xed electrode, a pair of conbushing l and accurately maintains variable elec: 4. tact springs and a Pyrex glass bearing setrode II concentric with fixed electrode I. A cured to said support barrel at one end, a silver jewel-like bushing I3 of Pyrex glass mounted electrode movable in said glass bearing concenconcentric in supportbarrel I2 provides an intric with said casing, a tubular insulator secured sulated bearing for variable electrode I I and to said electrode, a movable shaft secured to said reduces wear on said electrode to a minimum. m insulator, a xed threadedmember secured to To `aid in providing quietness of performance, a said support barrel at an end opposite said glass pair of beryllium copper, silver tipped, brush bearing, said shaft mounted in said xed threaded members Il are secured at a point of entrance member to provide the means to vary the conto support barrel I2. Members Il also maindenser capacity by moving said movable electrode tain the variable electrode Il at ground poten- 5.5 in. and out of said fixed electrode.

4. A variable condenser comprising a tubular metallic casing, a xed tubular electrode. a, tubular insulating support member secured to the inside of said casing, said xed tubular electrode capacity, a tubular insulating bushing interposed one end of said shaft-like movable elec- A trode and said threaded shaft and secured therewithin said casing, said ments to limit the motion -m both the maximum and minimum capacity position of said condenser.

5. A variable condenser comprising a tubular metallic casing, a fixed tubular electrode, a tubular insulating support member secured to the inside of said casing, said xed tubular electrode secured to said insulating support member at one end thereof, a. shaft-like movable electrode insulatingly supported within said casing by an insulating tubular bearing member located concen.

tric within said casing, means `including a threaded shaft to vary` vthe condenser capacity, a tubular insulating bushing interposed between one end of said shaft-like movable electrode and said threaded shaft and secured thereto, projecting abutments within said casing, said tubular insulating bushing positioned on said threaded shaft and cooperating with said abutments to limit the motion in both the maximum and minimum capacity position of said condenser.

FERDINAND JULIUS W. SCHOENBORN. I 

